Processes for separating electronic devices connected with one another in a body, by thinning a side of the body remote from the electronic devices, are used in semiconductor technology, for example. There, electronic devices are formed in a semiconductor wafer, with the devices having a substantially smaller thickness than the semiconductor wafer. This requires that the semiconductor wafer be thinned to the desired final thickness of the electronic devices. Semiconductor thinning may be accomplished by mechanically removing the semiconductor material or by etching. The electronic devices are then separated, generally by sawing. Since only good electronic devices or devices with predetermined electrical properties are to be selected and further processed, the electrical parameters of the electronic devices must be tested before the devices are selected and fed to subsequent processing apparatus. The subsequent processing apparatus is generally a bonder which attaches the electronic devices to a carrier. The electrical parameters must thus, be tested on the electronic devices connected with one another in the thinned wafer or on the separated devices.
Both of the above techniques for testing, involve considerable difficulties in practice. Separate electronic devices are difficult to handle. Furthermore, the backs of such devices are not accessible for measurements, since the devices are attached to a tape. If the electronic devices are measured before being mechanically separated, the problem arises that the measurements are relatively inaccurate, since both the mechanical and electrical properties of the electronic devices are subsequently affected by the separation, which is accomplished by sawing, for example. For the measurement, the thinned wafer must be mechanically handled, e.g., transported and fixed. This presents problems since a thinned wafer, which has a small thickness, is difficult to handle. Since the present trend is toward electronic devices with as little thickness as possible, which is particularly necessary for power devices, the handling of electronic devices in the thinned wafer form is becoming increasingly difficult. Thus, electrical testing and measuring of the electronic devices in a semiconductor wafer is in many cases problematic.
It is, therefore, an object of the present invention to provide a process for separating electronic devices which enables the electronic devices to be tested more reliably after the thinning of the body.